Mary, Sameul, or John Pinkerton in Seattle, WA?

Hello, my name is Scott Pinkerton and live in Olathe, KS, but grew up in the Olympia, Washington area.

My great gradma, Mary Pinkerton, married a Samuel Pinkerton and I beleive he passed away in 1975 or 1976- Mary passed away in 1987 or 1988 at the age of 95 or so. During their marriage they adopted two sons- John Pinkerton and Dwight Pinkerton and have lived in Western Washington state until their death. John Pinkerton passed away in the early 90's and is my fraternal grandfather- Dwight I assume is still alive but in his 80's.

My Father is Tim Pinkerton- son of John Pinkerton (lives in Seattle, WA) and my mothers name is Barbara Pinkerton who lives in Phoenix, AZ. I also have a sister named Chelsea.

I'm thinking we may be talking about the same Samuel Pinkerton as we've heard Allan Pinkerton was Sams great great Uncle. At some point (not sure where it is now) we had a letter from Lincoln that was sent to Allan and had been hadned down throughout the years and once Mary died, it vanished.